Playing mp4 gifs in Firefox on Opensuses Leap 42.2

From:
andrew cooke <andrew@...>

Date:
Wed, 21 Dec 2016 06:32:56 -0300

Some imgur gifv images were not displaying in Firefox. The following
four steps fixes this:
* Make sure you have the Packman repo configured (fro mcommunity repos)
* Load the gstreamer good, bad, and ugly plugins in yast
* From the command line as root do
zypper lr
zypper dup --from pacmanXXX
where packmanXXX is the exact name of the packman repo displayed by
the first command
* Restart firefox
Andrew